The present study was primarily designated as “Chino-Japanese cooperative study on physical fitness of junior track and field athletes” (1989) . The participants were male and female track runners of both countries ranging in age from 13 to 17 years.
Skeletal age and stature for each sex and athletic event for the present series were compared between the two countries. The data of the present series were then compared with the earlier series, that is, the reference data derived from “Chino-Japanese cooperative study on physical fitness of children and youth” (1986) .
Regarding the mean skeletal age of reference data (13 to 17 yrs.), the Japanese are more advanced (0.6 years in boys; 0.5 years in girls) than the Chinese, respectively. On the other hand, for the mean stature, the Chinese are taller (1.92cm in boys; 2.16cm in girls) .
In the present series, the mean differences for skeletal age between the two countries show a tendency to be smaller than those in the reference data (0.38 years for boys and 0.39 years for girls in 100m runners; 0.15 years for boys in 1500m runners and girls in 800m runners), respectively.
Although the mean differences of skeletal age between the two countries are becoming smaller, the stature of the Chinese boys and girls are getting taller than the Japanese (6.9cm in boys and 5.60cm in girls in 100m runners) . The mean differences are not so great as in 100m runners, however, it is 2.50cm in boys of 1500m runners and 4.05cm in girls of 800m runners.
Comparison of the athletic records between the two countries was made and in general little difference was found. The Chinese records are more complete than the Japanese and show statistically significant difference particularly in 17 years old.
In conclusion, the Chinese junior track runners seem to mature later skeletally or biologically than the Japanese, even though they are already taller than the Japanese. As a natural result, more gain in stature and more improvement in the athletic records will be expected for them. Otherwise some differences between the two countries in the process of sampling of the present study could be questioned.

INTRODUCTIONCephalic index (CI), the ratio of head breadth to head length, is widely used to categorise human populations. The aim of this study was to access the impact of anthropometric measurements on the CI of male Japanese university students.

METHODSThis study included 1,215 male university students from Tokyo and Kyoto, selected using convenient sampling. Multiple regression analysis was used to determine the effect of anthropometric measurements on CI.

RESULTSThe variance inflation factor (VIF) showed no evidence of a multicollinearity problem among independent variables. The coefficients of the regression line demonstrated a significant positive relationship between CI and minimum frontal breadth (p < 0.01), bizygomatic breadth (p < 0.01) and head height (p < 0.05), and a negative relationship between CI and morphological facial height (p < 0.01) and head circumference (p < 0.01). Moreover, the coefficient and odds ratio of logistic regression analysis showed a greater likelihood for minimum frontal breadth (p < 0.01) and bizygomatic breadth (p < 0.01) to predict round-headedness, and morphological facial height (p < 0.05) and head circumference (p < 0.01) to predict long-headedness. Stepwise regression analysis revealed bizygomatic breadth, head circumference, minimum frontal breadth, head height and morphological facial height to be the best predictor craniofacial measurements with respect to CI.

CONCLUSIONThe results suggest that most of the variables considered in this study appear to influence the CI of adult male Japanese students.

Adolescent ; Adult ; Body Height ; Cephalometry ; methods ; Cross-Sectional Studies ; Head ; anatomy & histology ; Humans ; Japan ; Male ; Reference Values ; Regression Analysis ; Students ; Universities ; Young Adult